The present invention relates to space and communications satellites, and more particularly, to regulating voltage of a power bus.
Many spacecraft use panels of solar cells to power the electrical equipment onboard the spacecraft. Such equipment typically includes communications transponders, sensors, detectors, and data processing equipment. Spacecraft typically include a battery for powering the loads when the spacecraft is out of the sun. Because of variations in power consumption needs of the spacecraft, variations in the amount of power generated by the solar panels and variations in the battery condition, spacecraft regulate the voltage and current on the spacecraft power bus which powers the electrical loads. Commonly, spacecraft bus regulating schemes are intended for relatively constant power loads. When subjected to transient or pulsating bus current loading, poor power quality is obtained. Poor power quality may affect the performance of various spacecraft functions.
It would, therefore, be desirable to accurately control the spacecraft power bus during transient loading.
The present invention provides bus voltage regulation and very low bus ripple and transients in the presence of large pulsating or transient bus current loading.
In one aspect of the invention, a regulating circuit that is coupled to a bus voltage and bus voltage return includes a solar array and a bus voltage limiting circuit electrically coupling the bus to the solar array. A battery is coupled to a battery discharge circuit and a battery charge circuit. The battery discharge circuit and the battery charge circuits are also coupled to the bus. A master bus regulator generates a voltage control signal. The control signal is coupled to the bus voltage limiting circuit, the battery discharge circuit, and the battery charge circuit. The voltage control signal is generated in response to the bus voltage.
In a further aspect of the invention, the master bus regulator may include an energy storage capacitor and a bi-directional DC to DC converter. Through the bi-directional DC to DC converter, the energy storage capacitor absorbs or provides transient energy.
In a further aspect of the invention, a method for regulating a voltage of a battery bus comprises the steps of coupling said battery charge current controller, the battery discharge controller, and the bus voltage limiter to the bus, generating a control voltage in response to a bus voltage, controlling a battery charge current controller, a battery discharge controller, and a bus voltage limiter in response to said control voltage, and regulating the bus voltage in response to the operation of the battery charge current controller, a battery discharge controller, and a bus voltage limiter.
One advantage of the invention is that ripple voltage resulting from large transient and pulsating bus current loading is minimized while maintaining tight DC regulation of the spacecraft bus.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.